A light emitting diode (LED) can be used in various lighting applications including residential, commercial, and industrial lighting systems. In typical LED lighting systems, an array of LEDs are coupled in series to produce a desired luminescence output. In a residential LED lighting system, a typical 120 VAC power source needs to be converted to DC power to drive the LED array. In conventional LED lighting systems, a driving circuit includes a rectifier to convert the AC power to a DC voltage and a boost converter to increase the converted DC voltage to a higher DC voltage. The boost converter can include a switching element that is driven by a current sense circuit. However, the current detected in the current sense circuit is susceptible to drift due to thermal changes in and around the driving circuit.
Thermal compensation in the driving circuit has been addressed using a thermistor. In particular, a thermistor can be used in conjunction with the current sense circuit to compensate for changes in current drift. However, tracking the changes in the current drift using a thermistor is inaccurate over a wide range of temperatures due to several factors, including the materials of the circuit elements. In addition, the use of the thermistor is relatively expensive.
Thus, a need exists for an improved LED driver circuit. A system and method that provides improved thermal compensation of a current sense circuit used in the LED driver would be particularly useful.